CMOS image sensor and method of fabricating the same

Abstract

A complementary metal-oxide semiconductor (CMOS) image sensor and a method of fabricating the same are disclosed. In a complementary metal-oxide semiconductor (CMOS) image sensor including a photodiode receiving irradiated light and generating electric charges, a plurality of conductive circuits each formed in different layers, a plurality of interlayer dielectrics insulating the conductive circuits, and a micro-lens formed of the interlayer dielectrics and focusing the irradiated light to the photodiode, the CMOS image sensor includes a lens formed in a dome shape on any one of the interlayer dielectrics and re-focusing the light focused by the micro-lens to the photodiode.

1. In a method of fabricating a complementary metal-oxide semiconductor (CMOS) image sensor, wherein the CMOS image sensor includes a photodiode receiving irradiated light and generating electric charges, a plurality of conductive circuits each formed in different layers, a plurality of interlayer dielectrics insulating the conductive circuits, and a micro-lens formed of the interlayer dielectrics and focusing the irradiated light to the photodiode, the method comprising:
 forming a lens for re-focusing the light focused by the micro-lens to the photodiode, wherein the step of forming a lens comprises:
 a first step of randomly forming one of the interlayer dielectrics and forming a nitride layer on an entire surface thereof; 
 a second step of depositing a photoresist layer on the nitride layer, and patterning the photoresist layer so that a set portion of photoresist remains in a corresponding area; 
 a third step of selectively removing the nitride layer by using the patterned photoresist layer as a mask, and removing the photoresist layer; 
 a fourth step of rounding corner portions of the selectively removed nitride layer by using a high frequency bias sputter etch process; and 
 a fifth step of forming the nitride layer in a dome shape by using a wet-etch process. 
 
 
   
   
     2. The method of  claim 1 , further comprising, before the second step, a step of performing a reflow process on the patterned photoresist. 
   
   
     3. The method of  claim 1 , wherein the fourth step comprises a radio frequency bias sputter etch process using helium (He) and a radio frequency bias sputter etch process using argon (Ar), which are performed simultaneously.